feat(rnote): Add Rnote module

modules/home/users/crumb/rnote.nix

@@ -0,0 +1,60 @@
+{ config, lib, pkgs, ... }:
+
+let cfg = config.sydnix.users.crumb.rnote;
+in {
+  options.sydnix.users.crumb.rnote = {
+    enable = lib.mkEnableOption "Rnote";
+  };
+
+  config = lib.mkIf cfg.enable {
+    home.packages = [
+      pkgs.rnote
+    ];
+
+    # C.f. https://github.com/gepbird/dotfiles/blob/main/modules/rnote.nix.
+    # Browse options with
+    #   dconf read /com/github/flxzt/rnote/engine-config \
+    #     | sed -e #  "s/'\(.*\)'/\1/" | jq
+    dconf.settings."com/github/flxzt/rnote" =
+      let
+        colour = r: g: b: a: { inherit r g b a; };
+        stylix = name: {
+          r = builtins.fromJSON config.lib.stylix.colors."${name}-dec-r";
+          g = builtins.fromJSON config.lib.stylix.colors."${name}-dec-g";
+          b = builtins.fromJSON config.lib.stylix.colors."${name}-dec-b";
+          a = 1.0;
+        };
+        weird-stylix = name: let c = stylix name;
+                             in lib.gvariant.mkTuple [c.r c.g c.b c.a];
+      in {
+        active-stroke-color = weird-stylix "base06"; # Old White
+        active-fill-color = weird-stylix "base06"; # Old White
+        engine-config = builtins.toJSON {
+          penholder.shortcuts = {
+            stylus_secondary_button.change_pen_style = {
+              style = "selector";
+              mode = "toggle";
+            };
+            stylus_primary_button.change_pen_style = {
+              style = "tools";
+              mode = "toggle";
+            };
+          };
+          document.background = {
+            color = stylix "base00"; # Sumi Ink 1
+            pattern_color = stylix "base06"; # Old White
+            format = {
+              show_borders = false;
+              border_color = colour 0.0 0.0 0.0 0.0;
+            };
+          };
+          pens_config = {
+            brush_config = {
+              stroke_color = stylix "base06"; # Old White
+              fill_color = stylix "base06"; # Old White
+            };
+          };
+        };
+      };
+  };
+}